It is conventional in oil wells to hydraulically pump oil from the ground by the use of a downhole pump positioned in a pump bottom hole assembly in the production tubing. In one embodiment, power fluid is pumped down the production tubing to actuate the downhole pump, and the well fluids and exhausted power fluid is produced through a fluid port in the bottom hole assembly and up the annulus between the production tubing and casing.
However, at various times it is necessary to stimulate the production formation in the well, for example, acidizing the well. At the present time, in order to accomplish this, it is necessary to withdraw both the hydraulic downhole pump along with the production tubing bottom hole assembly and production packer prior to fluid injection into the well producing formations. The operation of withdrawing the production tubing and its attachments requires moving a workover rig into position at the well and is both time-consuming and expensive.
The present invention is directed to an apparatus and method of stimulating such wells which avoid pulling the production tubing and the attached production packer and hydraulic bottom hole assembly, and therefore does not require the use of a workover rig. Instead, the present apparatus and method utilizes a coil tubing having an injector at its lower end with a sealing device. By pulling the hydraulic pump, but leaving the production tubing and bottom hole assembly in place, the coil tubing and sealing device of the present invention may sealingly seat in the bottom hole assembly which is left in place. This allows the well formation to be quickly and inexpensively stimulated.